The Great Comic Relief Bake Off, featuring Jo Brand and Stephen K Amos, was watched by an average of 3.8 million viewers. Photograph: Jon Cottam/BBC

BBC2 turned the heat up on its rivals with a Comic Relief edition of its big ratings winner, The Great British Bake Off, watched by nearly 4 million viewers on Monday night.

The Great Comic Relief Bake Off, featuring comics Jo Brand and Stephen K Amos among the contestants, was watched by an average of 3.8 million viewers, including 191,000 on the BBC HD channel, between 8.30pm and 9.30pm on Monday.

BBC2's hit show gobbled up its Channel 4 opposition, which included new natural history series Wild Things, which averaged 1.07 million viewers, a 3.9% share, between 8.30pm and 9pm.

The Comic Relief special also had the better of the opening half hour of Channel 4's Embarrassing Fat Bodies, watched by 1.56 million viewers, a 5.8% share, between 9pm and 10pm.

Embarrassing Fat Bodies also lost out to Channel 5's Celebrity Big Brother, which began its last week on air with 2.56 million viewers (9.5%), also between 9pm and 10pm.

BBC1 sitcom Miranda fell to its lowest audience of the series so far with an average of 6.4 million viewers, a 23.1% share, between 9pm and 9.30pm – possibly another victim of competition from BBC2's Comic Relief show.

It was down on the previous series low, of 6.8 million (25.9%) two weeks ago.

Miranda was neck and neck with the first half of ITV1 drama Lewis, watched by 6.3 million viewers (23.3%) across the hour between 9pm and 10pm.

But Lewis lost out to Mrs Brown's Boys, which followed Miranda on BBC1 with 7 million viewers, a 26.5% share between 9.30pm and 10pm.

Channel 4's highest rated show of the night was Dispatches, Secrets of the Supermarket Shop, which had 2.14 million viewers, an 8% share, between 8pm and 8.30pm.

It was up against BBC2's University Challenge, watched by 3.1 million viewers (11.7%), also between 8pm and 8.30pm.

The second episode of E4's Mad Fat Diary was watched by 397,000 viewers, a 2.1% share, between 10pm and 11pm, down on 498,000 viewers for last week's series opener.

BBC3 documentary Crazy for Party Drugs had 498,000 viewers, a 1.9% share, between 9pm and 10pm.

It was beaten by the second part of BBC4 documentary Lost Kingdoms of South America – AKA crazy for the Tiwanaku site on the Bolivian altiplano – which had 606,000 viewers, a 2.3% share, also between 9pm and 10pm.

All ratings are Barb overnight figures, including live, +1 (except for BBC channels) and same day timeshifted (recorded) viewing, but excluding on demand, or other – unless otherwise stated. Figures for BBC1, ITV, Channel 4 and Channel 5 generally include ratings for their HD simulcast services, unless otherwise stated

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